Arc welding with a.c. power and cored electrode



March 14, 1967 H. B. CARY 3,309,490

' ARC WELDING WITH A.C. POWER AND CORED ELECTRODE Original Filed May 12, 1965 FIG-l FIG- 2 vou's H G 3 VOLTAGE CURRENT l/W m AMPLITUDE \W W L4 INVENTOR.

TlME'-- HOWARD B. CARY ATTORNEYS v United States Patent 3,309,490 ARC WELDING WITH A.C. POWER AND CORED ELECTRODE I Howard B. Cary, Troy, Ohio, assignor to Hobart Brothers Company, Troy, Ohio, a corporation of Ohio Continuation of abandoned application Ser. No. 455,188, May 12, 1965. This application Mar. 14, 1966, Ser. No. 540,788

17 Claims. (Cl. 219-74) This application is a continuation of application Ser. No. 455,188, filed May 12, 1965, now abandoned, which in turn is a continuation-in-part of application Ser. No. 246,916, filed Dec. 26, 1962, now abandoned, and assigned to the same assignee as the present application. I

This invention relates to arc welding and more particularly to a gas shielded arc welding device and process utilizing commercially available alternating current electrical power and a continuous cored electrode containing slag forming and deoxidizing materials and including ionizing agents that promote conductivity to aid in maintaining an ignition during current reversal and during periods of momentary short circuit. The device constructed according to this invention is particularly useful in welding heavy materials where the welding current required is in the range of from 500 to 1500 amperes.

It has previously been proposed to use cored electrode in direct current welding to provide a slag shield for the molten Weld material. This slag shield excluded air from the molten weld and prevented oxidation and nitrating of the hot weld metal. It has also been proposed to use a gas shield in the area around the arc to exclude the air from the weld in the area in which the slag has not yet formed on the surface.

This gas shielded welding technique was particularly useful in direct current welding since a stable arc could be maintained. However, when welding heavy pieces which require extremely high welding currents, large magnetic fields are concentrated around the are which cause serious problems especially at the end of the welding operation. At the end of a work piece, the magnetic field becomes distorted and due to the high intensity of this field arc and the molten metal will be blown away from the end of the work piece thus preventing the welding operation from being completed. 'Various means have been suggested to correct this problem in high intensity direct current weld-ing including the addition of attachments which have been designed ot counteract the magnetic field. These corrective measures,'however, all add to the cost and reduce the efficiency of the welding operation.

The use of alternating currents has been suggested for high current welding operations since the problem of magnetic blow is materially reduced. With alternating currents, however, it has been difiicult to provide a stabilized arc and thus a satisfactory weld. This is due in part to the extinguishing of the are each time the current reverses polarity. Attempts to stabilize the arc and to insure re-ignition after current reversal have included techniques in submerged arc welding where a welding composition or flux is placed between the electrode and the work piece. The flux becomes conductive when heated and thus aids in maintaining the current flow.

It has also been suggested to use high open circuit voltages, for example, over 100 volts, in order to quickly reestablish the arc and to incorporate on the welding electrode an emissive coating to create an ionized atmosphere between the electrode and the article being welded to aid in reestablishing the arc after current reversal.

The obvious disadvantages of the submerged arc welding process is the lack of visibility of the joint during welding, and the problem of holding the welding com- 3,309,490 Patented Mar. 14, 1967 ICC position against the Work piece if in other than a horizontal position. The welding compositions or flux must also be perfectly dry which requires favorable weather conditions in open air operations.

The use of high open circuit voltage is hazardous especially in manual or semi-automatic operations where the operator handles one of the current carrying elements. Further, the addition of substanceswhich function to assist the metal transfer from the consumable electrode to the work piece necessitates providing a continuous feeding of the substances in a finely divided state into the welding arc. This not only requires special means but increases the cost of the welding-operation and tends to lower efficiency.

The present invention contemplates using commercial frequency (i.e., in most cases SO-cycle or 60-c yc1e) alternating current electrical power which is converted into a low voltage and a high current source by a suitable transformer. A sufiicient inductive reactance to maintain an adequate phase angle between the current and the voltageto insure the reestablishment of the arc immediately after current reversal is placed between the welding electrode and the transformer. The voltage versus cur-. rent characteristics of the entire power supply is designed to insure a stabilized arc and to minimize splatter from the electrodes.

1 The apparatus constructed according to the present'in vention further contemplates using a commercially available corded electrode containing slag forming and deoxidizing materials and ionizing agents. An air excluding gas shield is also provided to protect the molten metal in the weld from the harmful effects of nitrogen and oxygen in the air until the protective slag is formed.

Accordingly, it is an object of the invention to provide an electrical arc welding apparatus and method of arc welding capable of using commercially available alternating current power sources, an air excluding shield gas and a continuous cored electrode.

It is another object of this invention to provide an alternating current electrical arc Welding apparatus useful in the high intensity current ranges which reduces the eifect of magnetic blow. V v

It is another object of this invention to provide a welding apparatus employing alternating current where the electrode is continuously fed into the are at a feed rate related to the desired deposition rate of the weld.

A further object of the invention is to provide novel arc welding electrodes for use with alternating current welding appartus.

Other objects and advantages of the invention will be apparent from the following description, the accompany ing drawings and the appended claims.

In the drawings:

FIG. 1 is a view in elevation, partly in perspective and partly in section of a suitable welding apparatus as constructed in this invention with an AC. electrical power supply therefor shown schematically;

FIG. 2 is a curve showing the relationship between the voltage and current at the output of the power supply; and

FIG. 3 is a chart showing the phase relationship of the voltage and current in the welding circuit with respect to time.

In FIG. 1 a welding head 10 is shown feeding a continuous, consumable cored electrode 11 through the h'ead 10 to the work piece 13 by friction rolls 14 and 15. The

feed rate of the electrode is determined by the desired deposition rate of the weld. Suitable drives for the rolls 14 and 15 are well known.

The welding head 10 comprises a hollow body portion 17 having a central passageway 18 for passage of the cored electrode 11. An integral nozzle 20 on the lower end of the welding head includes a nozzle chamber 22 which receives shielding gas for discharge from the nozzle around the electrode to provide a gas shield at the arc end as shown at 24.

A conduit 26 which is suitably connected to the welding head communicates with a source of shielding gas, such as carbon dioxide, argon, helium, or mixtures thereof, and which may include up to five percent by volume of oxygen. Introduction of the gas into the nozzle as indicated by the arrows will cause the gas to exclude the air around the arc and thus form alshield at the weld to promote purity of the weld. The electrode 11 comprises a hollow'tube of metal, such as mild steel, which is filled with slag forming and deoxidizing materials 28 and may include an ionizing agent. Alternating current is supplied to the electrode through wire 30 and a metal contact shoe 31. The contact shoe is yieldably held in sliding engagement with electrode 11 by coil spring 33. The circuit is completed by wire 35, normally referred to as a ground wire, electrically connected to work piece 13 through contact 36.

The alternating current for the welding apparatus may be supplied, for example, from a suitable transformer 40. The primary winding 41 of transformer 40 may be connected to a source of commercial alternating current. One side of secondary winding 42 is connected to the work piece 13 through wire 35. An inductive reactance 43 is placed between the electrode and secondary winding 42. The inductive reactance 43 acts to insure the continuous reestablishment of the are after current reversal or each time the current passes through zero, and preferably is adjustable to provide for a stable are over a wide range of welding currents.

The power supply constructed according to this invention gives a controlled current output that insures a proper weld; When a short circuit occurs between the electrode 11 and the article 13 being welded, as due to a drop of metal therebetween, the current output from the power supply increases an amount sufiicient to melt the electrode and move the drop into the weld. The current does not increase to a value which would cause the molten metal to explode resulting in splatter.

FIG. 2 shows a typical voltage versus curves of the power supply of this invention. The open circuit voltage may be, for example, 80 volts, while the usable voltage range may-be between 35 and 45 volts. Under normal welding conditions, the voltage across the arc may be 45 volts. However, during a momentary short circuit, the voltage would decrease, and the current increase an amount large enough to melt the metal, but not large enough to produce splatter.

FIG. 3 shows the phase relationship between the voltage and the current at the arc. Line 50 represents the current and line 51 represents the voltage across the arc. The are is extinguished when the current passes through zero and reverses direction as at 52. Since the voltage leads the current as shown by the curves, the voltage will already be at a substantial magnitude at the time the arc is extinguished and will thus aid in the reestablishment of the arc.

The composition used in the cored electrode contains as essential constituents oxides and silicates of potassium or titanium, deoxidizers such as manganese, silicon or titanium, and some also contain a fluoride such as cryolite, potassium, silica fluoride, and calcium fluoride. Suitable compositions useful for application to the welding through the core of electrodes are given in the following tables:

Compositions for cored electrodes TABLE '1 Parts by weight Manganese 16 Ferrosilicon 14 Titanium dioxide (rutile) S Ferric oxide (magnetite) TABLE II Parts by Range Weight Potassium Titanate '45 40-50 Ferromanganese 18 15-25 Ferrosilicon 14 12-16 Iron (60 mesh powd 8 6-10 Ferric Oxide (Magnetite) 15 1220 TABLE III Parts by Range Weight Potassium Titanate 20 16-25 Ferromanganese 22 18-24 Ferrosilicon 17 15-20 Aluminum Silicate (Kyanite) 10 8-12 Titanium Dioxide (Rutile) 11 8-13 TABLE IV Parts by Range Weight Patassium Titanate 30 20-40 Ferromanganese 25 15-45 Ferrosilicon r 15 12-25 Ferric Oxide (Magnetite) 15 Trace-20 TABLE V Parts by Range Weight Potassium Silicate 20 15-30 Titanium Dioxide 30 20-40 Ferromanganese 25 20-40 Ferrosilicon 10 5-15 Sodium aluminum flno e ry 10 8-14 Calcium fluoride (Fluorspar) 3 2-5 TABLE VI Parts by Range Weight Potassium Silicate 25 15-30 Titanium Dioxide l 30 20-40 Ferromanganese 15 20-40 Ferrosilicon 10 5-15 Ferrotitanimn 0 Trace-10 Iron 0 Trace-30 TABLE VII Parts by Range Weight Potassium Titanate .Q 30 20-40 Ferromanganese 20 15-45 Ferrosilicon 15 12-25 Iron Oxide 0 Trace-20 TABLE VIII Parts by Range Weight Rubidium Carbonate 5 4-8 Titanium Dioxide 1 20 17-35 Feiromanganese 18 15-49 Ferrosilicon 15 12-25 Iron Oxide 0 Trace-20 In the foregoing electrode compositions, manganese, silicon and titanium are deoxidizers. The fluorides promote fusion. The compounds of potassium, titanium, cesium and rubidium are ionizing agents and function to promote the restoration of welding currents immediately after current reversal. It is possible to include the deoxidizers'in the mild steel sheath or tube instead 05 as a part of the core material.

The cored electrode comprises from 12 to 18 percent by weight of core material. The outer sheath of the metal electrode may be composed of a mild steel containing ap-' proximately 0.10 percent carbon, 0.32-0.60 percent manganese and 0.04 percent silicon.

In accordance with one embodiment of the invention, the welding process is carried out with an are created by an alternating current power supply having an open circuit voltage of between 50 and 80 volts. The current supplied to the weld is between 500 and 1500 amperes. Air is eliminated from the weld by supplying a shielding gas of carbon dioxide, argon or helium, or mixtures thereof, to the arc region at approximately ten to sixty-five cubic feet per hour through the nozzle described.

To weld a one inch thick plate of mild steel, for example, a A; inch electrode composed of a mild steel outer sheath and a core composition as described in Table I may be used. With an open circuit voltage of 72 Volts, the current drawn during the welding operation will be approximately 800 amperes and the voltage across the arc will be approximately 40 volts.

The apparatus and process described is particularly useful for large current welding requirements, such as in the range from 500 to 1500 amperes. The use of alternating electrical current with the phase angle between the current and voltage controlled, and the use of a shielding gas permits high current welding without requiring that the arc be submerged in a powdered or granulated welding composition.

While the process herein described, and the' form of apparatus for carrying thisprocess into eifect, constitute a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise process and form of apparatus, and that changes may be made in either without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. An arc welding electrode for welding steel by an are created by an alternating current power supply, said electrode consisting of a metallic tube filled with a composition comprising by weight 20 to 40 parts of potassium titanate, 15 to 45 parts of ferromanganese, 12 to 25 parts of ferrosilicon, and a trace to 20 parts of iron oxide.

2. An arc welding electrode as defined in claim 1 wherein the iron oxide is ferric oxide.

3. An arc welding electrode for welding steel by an arc created by an alternating current power supply, said electrode consisting of a metallic tube filled with a composition comprising by weight 40 to 50 parts potassium titanate, 15 to 25 parts ferromanganese, 12 to 16 parts ferrosilicon, 12 to 20 parts ferric oxide, and 6 to parts iron powder.

4. An arc welding electrode for welding by an are created by an alternating current power supply, said electrode consisting of a metallic tube filled with a composition comprising by weight 16 to 25 parts of potassium titanate, 18 to 24 parts ferromanganese, to parts ferrosilicon, 8 to 12 parts aluminum silicate, and 8 to 13 parts titanium dioxide.

5. An arc welding electrode for welding by an arc created by an alternating current power supply, said electrode consisting of a metallic tube filled with a composition comprising by weight 15 to 30 parts potassium silicate, 20 to 40 parts titanium dioxide, 20 to 40 parts ferromanganese, 5 to 15 parts ferrosilicon, 8 to 14 parts sodium aluminum fluoride, and 2 to5 parts calcium fluoride.

6. An arc welding electrode for welding by an arc createdjby alternating current power supply, said electrode consisting of a metallic tube filled with a compostion comprising by weight 15 to 30 parts of potassium silicate, 20 to 40 parts of titanium dioxide, 20* to 40 parts of ferromanganese, 5 to 15 parts of ferrosilicon, a trace to 10 parts of fer-rotitanium, and a trace to 30 parts of iron.

7. An arc welding electrode for welding by an arc created 'by an alternating current power supply, said electrode consisting of a metallic tube filled with a composition comprising by weight 4 to 8 parts of rubidium carbonate, 17 to 35 parts of titanium dioxide; 15 to 49 parts of ferromanganese, 12 to 25 parts of ferrosilicon and 0 to 20 parts of iron oxide.

8. An arc welding electrode for welding by an are created by an alternating current power supply, said electrode consisting of a metallic tube filled with a composition comprising by weight 4 to 17 parts of cesium carbonate, 17 to 35 parts of titanium dioxide,-20 to 40 parts of ferromanganese, 5 to 15 parts of ferrosilicon, 0 to 10 parts of ferrozirconium,and 0 to 30 parts of iron oxide. 9. A process of electric arc welding with an open are which comprises the steps of supplying an alternating electric current at commercial frequency and in the order of at least 500 amperes to a continuous consum-rnable cored electrode connected in series with an inductive reactance to develop an are between the said electrode and an article being welded, said inductive reactance being the major element aifecting the application of electrical power from the alternating current source to the arc and being of sufficient reactance to cause the current flowing through the arc to lag the voltage applied between the electrode and the article by an amount suflicient to establish a sufficient open circuit voltage across the are when the current is essentially zero to reestablish the arc immediately after current reversal solely under promotion of the available open circuit voltage and the action of ionizing agent present in the core material of the electrode, adjusting the reactance to adjust the phase angle between the voltage and the current to an amount sufiicientto create and maintain a stabilized arc,

employing an electrode comprising a tubular metallic sheath and core material contained therein in the amount of from 12 to 18 percent by weight of the total weight of the electrode and including an ionizing agent as an essential ingredient, the core material consisting of 16 parts by weight of manganese, 14 parts by weight of ferrosilicon, 55 parts by weight of rutile, and 15 parts by weight of magnetite.

feeding the electrode toward the article being welded at a rate sufficient to maintain continuous welding at the arc and simultaneously causing relative motion between an arc and the eletrode along a desired line of weld, and directing an inert arc excluding shield of gas toward the article and around the arc.

10. A process of electric arc welding with an open are which comprises the steps of supplying an alternating electric current at commercial frequency and in the order of at least 500 amperes to a continuous consumable cored electrode connected in series with an inductive reactance to develop an are between the said electrode and an article being welded, said inductive reactance being the major element affecting the application of electrical power from the alternating current source to the arc and being of suflicient' reactance to cause the current flowing through the arc to lag the voltage applied between the electrode and the article by an tion between an arc and the electrode along a desired line of weld, and directing an inert air excluding shield of gas toward the article and around the arc.

op an arc between the said electrode and an article being welded, said inductive reactance being the major element affecting the application of electrical power from the alternating current source to the arc amount sufficient to'establish a sufiicient open circuit and being of sufficient reactance to cause the current voltage across the arc when the current is essentially flowing through the arc to lag the voltage applied zero to reestablish the are immediately after current between the electrode and the article by an amount reversal solely under promotion of the available sufiicient to establish a sufficient open circuit voltage open circuit voltage and the action of ionizing agent across the are when the current is essentially zero present in the core material of the electrode, 10 to reestablish the arc immediately after current readjusting the reactance to adjust the phase angle beversal solely under promotion of the available open tween the voltage and the current to an amount sufiicircuit voltage and the action of ionizing agent prescient to create and maintain a stabilized arc, ent in the core material of the electrode,

employing an electrode comprising a tubular metallic adjusting the reactance to adjust the phase angle besheath and core material contained therein in the tween the voltage and the current o an amount sufamount of from 12 to 18 percent by Weight of the ficient to create and maintain a stabilized arc, total weight of the electrode and including an ionizemploying an electrode comprising a tubular metallic ing agent as an essential ingredient, the core material sheath and core material contained therein in the consisting of 20 to 40 parts by weight of potassium amount of from 12 to 18 percent by weight of the titanate, 15 to 45 parts by weight of ferromanganese, 20 total weight of the electrode and including an ioniz- 12 to parts by weight of ferrosilicon, and a trace ing agent as an essential ingredient, the core material to 20 parts by weight of iron oxide, consisting of 16 to 25 parts by weight of potassium feeding the electrode toward the article being welded te, 8 to 24 parts by weight of ferromanganese, at a rate sufiicient to maintain continuous welding 15 to 20 parts by weight of ferrosilicon, 8 to 12 parts at the arc and simultaneously causing relative mo- 25 y Weight of aluminum Silicate, and 8 to 13 Parts y weight of titanium dioxide,

feeding the electrode toward the article being welded at a rate suflicient to maintain continuous welding at the arc and simultaneously causing relative motion 11. The process as defined in claim 10 wherein the iron oxide in the core material of the electrode is ferric oxide.

12. A process of electric arc welding with an open are which comprises the steps of supplying an alternating electric current at commercial between an arc and the electrode along a desired line of weld, and directing an inert air excluding shield of gas toward the article and around the arc.

14. A process of electric arc welding with an open are which comprises the steps of supplying an alternating electric current at commercial frequency and in the order of at least 500 amperes to a continuous consumable cored electrode connected in series with an inductive reactance to develop an arc between the said electrode and an article being welded, said inductive reactance being the at the arc and simultaneously causing relative motion between an arc and the electrode along a desired line of weld, and directing an inert air excluding shield of gas toward the article and around the arc.

frequency and in the order of at least 500 amperes to a continuous consumable cored electrode connected in series with an inductive reactance to develop an are between the said electrode and an article major element affecting the application of electrical being Welded, Said inductive reactance being the power from the alternating current source to the major element affecting the application of eleetl'leal arc d b i f ffi i t reactance to cause th power from the alternating current source to the arc current flowing through the arc to lag the voltage and being of sufiicient reactance to cause the current applied between the electrode and the article by an flowing through the are to g the Voltage pp amount sufficient to establish a sufiicient open circuit between the electrode and the article y an amount voltage across the are he th current i 655m. sufiicicnt to establish a sufiicient open circuit voltage tially zero to reestablish the arc immediately after across the are When the ctlrfent is essentially Zero current reversal solely under promotion of the availt0 reestablish the are immediately after ehl'l'ent able open circuit voltage and the action of ionizing Versal solely llhdel' Promotion of the available p agent present in the core material of the electrode, Circuit Voltage and the action of ionizing agent P adjusting the reactance to adjust the phase angle beent in the Core material of the electrode,

tween the voltage and the current to an amount adjusting the reactance to adjust the Phase angle suflicient to create and maintain a stabilized arc, tween the Voltage and the current to an amount employing an electrode comprising a tubular metallic fieient t0 create an maintain StabiliZed a sheath and core material contained therein in the employing an electrode Comptlslhg metallic amount of from 12 to 18 percent b weight of h sheath and core material contained therein in the total weight of the electrode and including an ionizamount of from 12 to 18 Percent y Weight of the ing agent as an essential ingredient, the core material total Weight of the electrode and including an iOhlZ- Co sisting of 40 to 50 parts by weight of potassium ing agent as an essential ingredient, the core material titanate, 15 to 25 parts by weight of ferromanganese, Consisting of 15 to 30 Pa y W ig t f potassium 12 to 16 parts by weight of ferrosilicon, 12 to 20 Silicate, 20 to 40 Parts y Weight of titanium dioxide, parts by weight of ferric oxide, and 6 to 10 parts by 20 to 40 Parts y Weight of terfonlanganese, 5 to 15 weight of iron powder, parts by weight of ferrosilicon, 8 to 14 parts by feeding the electrode toward the article being welded Weight of Sodium talulnlnum fluoride, and 2 t0 5 at a rate suificient to maintain continuous welding Parts y Weight of ealelhm fluoride,

feeding the electrode toward the article being welded at a rate suflicient to maintain continuous welding at the arc and simultaneously causing relative motion between an arc and the electrode along a desired line of weld, and directing an inert air excluding shield of gas toward the article and around the arc.

15. A process of electric arc welding with an open are which comprises the steps of supplying an alternating electric current at commercial frequency and in the order of at least 500 amperes 13. A process of electric arc welding with an open are which comprises the steps of supplying an alternating electric current at commercial frequency and in the order of at least 500 amperes to a continuous consumable cored electrode connected in series with an inductive reactance to develto a continuous consumable cored electrode connected in series with an inductive reactance to develop an are between the said electrode and an article being welded, said inductive reactance being the major element affecting the application of electrical power from the alternating current source to the arc and being of suflicient reactance to cause the current flowing through the arc to lag the voltage applied between the electrode and the article by an amount suificient to establish a sutficient open circuit voltage across the are when the current is essentially zero to reestablish the are immediately after current reversal solely under promotion of the available open circuit voltage and the action of ionizing agent present in ing agent as an essential ingredient, the core material consisting of 4 to 8 parts by weight of rubidium carbonate, 17 to 35 parts by weight of titanium dioxide, to 49 parts by weight of ferromanganese, 12 to 25 parts by weight of ferrosilicou, and a trace to parts by weight of iron oxide,

feeding the electrode toward the article being welded at a rate sufiicient to maintain continuous welding at the arc and simultaneously causing relative motion between an arc and the electrode along a desired line of weld, and directing an inert air excluding shield of gas toward the article and around the arc.

17. A process of electric arc welding with an open arc which comprises the steps of the core material of the electrode, 15 supplying an alternating electric current at commercial adjusting the reactance to adjust the phase angle befrequency and in the order of at least 500 amperes ween the voltage and the current to an amount sufto a continuous consumable cored electrode conficient to create and maintain a stbilized arc, nected in series with an inductive reactance to deemploying an electrode comprising a tubular metallic velop an are between the said electrode and an article sheath and core material contained therein in the 20 being welded, said inductive reactance being the amount of from 12 to 18 percent by weight of the major element affecting the application of electrical total weight of the electrode and including an ionizpower from the alternating current source to the arc ing agent as an essential ingredient, the core mateand being of suflicient reactance to cause the current rial consisting of 15 to 30 parts by weight of potasflowing through the arc to lag the voltage applied sium silicate, 20 to 40 parts by weight of titanium between the electrode and the article by an amount dioxide, 20 to 40 parts by weight of ferromanganese, sufficient to establish a sufficient open circuit voltage 5 to 15 parts by weight of ferrosilicon, a trace to 10 across the are when the current is essentially zero to parts by weight of ferrotitanium and a trace to reestablish the arc immediately after current reversal parts by weight of iron, solely under promotion of the available open circuit feeding the electrode toward the article being welded voltage and the action of ionizing agent present in at a rate sufficient to maintain continuous welding at the core material of the electrode, the arc and simultaneously causing relative motion adjusting the reactance to adjust the phase angle bebetwcen an arc and the electrode along a desired line Ween the voltage and the current to an amount sufof weld, and directing an inert air excluding shield ficient to create and maintain a stabilized arc, of gas toward the article and around the arc. employing an electrode comprising a tubular metallic 16. A process of electric arc welding with an open arc sheath and core material contained therein in the which comprises the steps of amount of from 12 to 18 percent by weight of the supplying an alternating electric current at commercial total weight of the electrode and including an ionizfrequency and in the order of at least 500 amperes 4O ing agent as an essential ingredient, the core mateto a continuous consumable cored electrode conrial consisting of 4 to 17 parts by weight of cesium nected in series with an inductive reactance to decarbonate, 17 to 35 parts by weight of titanium divelop an arc between the electrode and an article oxide, 20 to 40 parts by weight of ferromanganese, being welded, said inductive reactance being the Ste 15 parts by weight of ferrosilicon, a trace to 10 major element affecting the application of electrical parts by weight of ferrozirconium, and a trace to 30 power from the alternating current source to the arc parts by weight of iron oxide, and being of sufiicient reactance to cause the current feeding the electrode toward the article being welded flowing through the arc to lag the voltage applied at a rate suflicient to maintain continuous welding at between the electrode and the article by an amount the arc and simultaneously causing relative motion sufficient to establish a sufiicient open circuit voltage between an arc and the electrode along a desired line across the arc when the current is essentially zero to of weld, and directing an inert air excluding shield reestablish the are immediately after current reversal of gas toward the article and around the arc. solely under promotion of the a vailable open circuit References Cited by the Examiner voltage and the action of ionizing agent present 1n the core material of the electrode, UNITED STATES PATENTS adjusting the reactance to adjust the phase angle be- 2,694,764 11/1954 Muller 219-146 X ween the voltage and the current to an amount suf- 2,909,778 10/1959 Landis et a1 219'- 146 X ficient to create and maintain a stbilized arc, 2,951,931 9/ 1960 Danhier 2l974 employing an electrode comprising a tubular metallic 3,051,822 8/1962 Bernard et 1 219 74 sheath and core material contained therein in the 3,117,215 1/1964 Ramsey 219l31 X amount of from 12 to 18 percent by weight of the total weight of the electrode and including an ioniz- JOSEPH V. TRUHE, Primary Examiner, 

1. AN ARC WELDING ELECTRODE FOR WELDING STEEL BY AN ARC CREATED BY AN ALTERNATING CURRENT POWER SUPPLY, SAID ELECTRODE CONSISTING OF A METALLIC TUBE FILLED WITH A COMPOSITION COMPRISING BY WEIGHT 20 TO 40 PARTS OF POTASSIUM TITANATE, 15 TO 45 PARTS OF FERROMANGANESE, 12 TO 25 PARTS OF FERROSILICON, AND A TRACE TO 20 PARTS OF IRON OXIDE. 